The invention concerns a covering structure of the driving place of operative machines, particularly suitable for executing road-works.
It is known that the driving place of operative machines for road-works is protected by a covering structure in order to protect the driver during the use of the machine.
The covering structures belonging to the known technique which are commonly used, are formed of a canopy which insists on the frame of the operative machine by supporting telescopic elements which permit its lifting and lowering by manual manuvres.
Solutions of this kind present therefore manoeuvring problems because the manual lifting and lowering of the canopy is quite uneasy, first of all when it presents considerable dimensions and weights.
Besides, when the canopy is of large dimensions it is easy that during the lifting and the lowering it arranges itself in an inclined position, forcing in an oblique way on the telescopic supporting elements and obliging the operator to intervene in order to unfix it.
Another inconvenience is also wherein the lifting of the canopy, beginning from its position completely lowered, takes place inside the driving place and for entering it the operator is obliged to slip in under the canopy and therefore to make movements in uneasy conditions which could sometimes involve the danger of work accidents.
In order to obviate to such inconveniences, covering structures in which the canopy is provided with articulated supporting elements which are pushed by actuators with compressed gas, are known.
Such solutions present however problems for the closing of the canopy similar to the problems previously mentioned.
Indeed if the presence of actuators with compressed gas makes easy the lifting of the canopy which takes place in an automatic way by thrust of the actuators themselves, it should be manually lowered in order to be closed again, and therefore the same problems previously described, and that is the canopy can fix itself in an oblique way forcing against the elements which support it, could arise again.
The present patent intends to overcome the mentioned inconveniences.
In particular one of the purposes of the invention is for realising a covering structure of the driving place of operative machines for road-works which doesn't present difficulties for being lowered and lifted.
It is another purpose for the covering structure of the invention is not subjected to warp or incline itself pushing in an oblique way against the supporting elements and therefore to block itself when it is lowered.
It is another purpose for the canopy which forms the covering structure of the invention can be easily manoeuvred by the outside of the machine before the operator slips in the driving place.
The mentioned purposes are achieved by the realisation of a covering structure of the driving place of operative machines which, according to the main claim, comprises a canopy which insists on the frame of said operative machine by supporting elements and shifting means suitable for lifting it and it is wherein each of said supporting elements is formed by at least a couple of braces made movable by at least one of said shifting means, which is arranged between them and which has its compass movement in order to lift said canopy, being said braces, when said canopy is lifted, arranged in an angular position according to an amplitude angle smaller than 180.degree., suitable for favouring their folding when said canopy is lowered.
According to a preferred embodiment the canopy, which presents in plan a substantially rectangular shape is supported in correspondence with the vertexes by supporting elements which are formed of an upper rod rotatably secured or pivoted to the frame of said machine, where the clear extremities of said upper and lower rods are pivoted to one another. An hydraulic cylinder for the lifting and the lowering of said canopy is arranged in between said upper and lower rods.
Said hydraulic cylinders are fed by a same pressurised circuit by which the canopy is lifted when said hydraulic cylinders are fed by pressurised oil and vice-versa it is lowered when said hydraulic cylinders are put for draining by suitable command valves.
Advantageously the commanding device of the power of the hydraulic circuit which feeds said hydraulic cylinders can be activated not only from the driving place but also from the outside of the operative machine in order that the operator can lift the canopy before entering the driving place.
Advantageously, when the canopy is in a completely lifted position, the rods which are the supporting elements are in an angular position in order to favour the descending of the canopy itself which keeps itself in a plane position during the lowering, avoiding this way its arrangement in an oblique position and its forcing against the supporting elements, fixing itself.